Process for producing photographic emulsions

ABSTRACT

A PROCESS FORPRODUCING SILVER HALIDE PHOTOGRPAHIC EMULSIONS WHICH COMPRISE DISSOLVING PHOTOGRAHIC SENSITIZING OR DESENSITIZING DYES IN AN AQUEOUS SOLUTION OF A SURFACE ACTIVE AGENT COMPRISING A HYDROPHILIC GROU SELECTED FROM THE GROUP CONSISTING OF -SO3-, -OSO3-, OR COO- AND ADDING THE RESULTING SOLUTION TO THE SILVER HALIDE PHOTOGRAPHIC EMULSION.

nited States Patent vs. Cl. 96101 16 Claims ABSTRACT OF THE DISCLOSURE A process for producing silver halide photographic emulsions which comprise dissolving photographic sensitizing or desensitizing dyes in an aqueous solution of a surface active agent comprising a hydrophilic group selected from the group consisting of -S0 OSO or CO0- and adding the resulting solution to the silver halide photographic emulsion.

BACKGROUND. OF THE INVENTION 'Field of the invention The present invention relates to a process for producing new photographic sensitive elements and particularly to an improved process for spectrally sensitizing photo'- graphic emulsions.

Description of the Prior Art Most of the spectral sensitizing dyes used for the spectral sensitization of silver halide photographic emulsions are insoluble in water. In order to dissolve these dyes, a large amount of an organic solvent miscible with water, such as methanol, ethanol, propanol, acetone, etc., is required. For instance, a dye such as 3,3-diethyl-5,5- diphenyl-9-ethyl-oxacarbocyanine thiocyanate. can barely be dissolved in methanol when 1 part by weight thereof is added to 10,000 parts by weight of methanol. If a spectral sensitizing dye dissolved in such a large amount of organic solvents is added until a sufiicient photographic speed is obtained, sometimes as much as 30 cc. of the organic solvent per 100 g. of the silver halide photographic emulsions must be added.

In common silver halide photographic emulsions which contain 3 to g. or so of gelatin or another hydrophilic binder per 100 g. of the. emulsion, aggregation of the emulsion is caused by a kind of hydration phenomena known as coacervation when such a large amount of organic solvent (for example, methanol) is added. In general, the higher the ratio of the organic solvent to the binder in the emulsion is, the more easily this phenomena occurs. Moreover, troubles such as the formation of lumps and streaks are easily caused when coating such emulsions on a support. In the case of coating-the emulsions to a support, it is necessary to increase the amount of silver halide included in the unit weight of emulsions by concentrating the system in order to increase the speed of coating while keeping a definite drying load. When solution in organic solvents for addition to" silver halide photographicemulsions; It is well kno'wnthatdyes'such 'ice as a vat dye are soluble in an aqueous solution of surface active agents (refer, for example, to A. M. Mankowich, Ind. Eng. Chem., 44, 1151-1159 (1952); J. W. McBain & R. C. Merrill, Ind, Eng. Chem., 34, 915-919 (1942); and J. W. McBain & T. M. Woo, J. Am. Chem. Soc., 60, 223- 227 (1938)).

Summary of the Invention The present inventors have found that photographic sensitizing or desensitizing cyanine dyes incorporated silver halide photographic emulsions are soluble in an aqueous solution of certain kinds of surface active agents, and that when such aqueous dye-surface active agent solutions are added to silver halide photographic emulsions, the photographic speed obtained is equal to or more than that obtained from silver halide emulsions in which the dye is added as a solution dissolved in organic solvents.

Furthermore, the present inventors have found that spectral sensitizing dyes which are poorly soluble in organic solvents such as alcohols (methanol, ethanol and propanol, etc.) and acetone can easily be dissolved in an aqueous solution of such surface active agents.

The present invention should, however, be distinguished from Japanese Patent Publication Sho 44-27555 and British Pat. 1,138,114.

In the above-mentioned patents, water is used as dye solvents. However, these patents are clearly different from the present invention in that it is necessary to adjust the pH value of the dye solution to 6-7.5 by adding organic bases, and surface active agents are not added. Further, the spectral sensitizing dyes described in the above patents are not always water-soluble, namely, many kinds of the dyes do not dissolve if ultrasonic waves are not applied thereto.

The present invention should also be distinguished from French Pat. 1,482,774 and British Pat. 1,154,781. In these patents, though surface active agents such as sodium alkylnaphthalene sulfonates are required, these surface active agents are used as an emulsifier for emulsifying the organic solvent in which the spectral sensitizing dyes are dissolved. Accordingly, these patents are clearly different from the present invention, and also require an emulsifying step.

In the present invention, no specific apparatus is required, and prior art apparatus used for dissolving sensitizing dyes can be used. Moreover, however, it is possible to shorten the period of time, necessary to dis solve the dyes as compared to the prior art.

Detailed Description of the Invention Although the solvent used in examples of the present invention is solely water, it may contain, if desired, a small amount of organic solvents (for example, up to about 30% by weight).

According to the present invention, uniformity of coating can be kept upon coating'the photographic emulsions to a support, particularly at high coating speeds (for example, 30 m./min. m./min.) when organic solvents are not added, or even if added in the small amount recited into the aqueous solvent for the photographic sensitizing or desensitizing dyes.

According to the present invention, it is possible not only to greatly increase the concentration of the dye solutions as compared with the prior art processes for dissolving using organic solvents, since the solubility of the dyes becomes higher, but to vary, if desired, the concentration of the dye solutions in a wide range.

As the silver halide emulsions in the present invention, silver chloride, silver chloro-bromide, silver bromide, silver iodo-bromide, silver chloro-iodo-bromide or silver chloro-iodide in a hydrophilic colloid such as gelatin and derivatives thereof, albumin, arabic gum, agar-agar, syn- 3 thetic resin (such as polyvinyl alcohol, polyvinyl pyrrolidine), water soluble cellulose derivatives (such as alkyl ester of carboxy cellulose, hydroxy ethyl cellulose, carboxy methyl hydroXy-ethyl cellulose) or other hydrophlio synthetic or natural resins can be used.

In the production of the photographic sensitive elements spectrally sensitized in accordance with the present invention, antifogging agents, stabilizers, toning agents, hardening agents, wetting agents, plasticizers, development accelerators, surface active agents for coating dyes for inhibiting irradiation effects, fluorescent agents, ultraviolet absorbers, filter dyes and color formers may be added for their art-recognized function.

If a surface active agent suitable for coating (for example, saponin) is used as the surface active agent in the present invention, a part or whole of the surface active agent for coating can be eliminated.

The surface active agents used in the present invention are those comprising a combination of a hydrophobic group and a hydrophilic group such that the amount of surface active agents relevant to the present invention may be varied according to the dyes employed in combinaton with the surface active agents. The amount greater than the critical concentration for the formation of micelle for the surface active agents (hereinafter referred to as C.M.C.) is preferred in the present inven tion.

The C.M.C. is described in Ichiro Nishi et al. Kaimen Kasseyai Binran as SO OSO and --COO. Preferred hydrophobic groups are aromatic groups substituted by saturated or unsaturated hydrocarbon groups having up to 18 carbon atoms, or aliphatic hydrocarbon groups having up to 20 carbon atoms. The following compounds are examples of such surface active agents.

1. CnHaa-COOCHzCEhSOzNa 2. SOaNa C talks-CH C O ONa.

3. CsHuOOC-CH-SOaNfi 4. CuHzs-C O-N-CHzCHzSOaK 5; CuHaa-C ONCH2CHzSOaN8 em -@-o-cmorno-omorno-cmomsotNa cm o-(cmornon-wmn-smm S OaNa S OaNa S OzNa 11 (R and R'=H or C -C alkyl group, and n=15) p and q each represent a positive integer where p+ =5 29. N-CH:

CnHazamong-ems On HzCHrO-(CHzh-S O Na 30. Saponin Typical examples of photographic sensitizing or desensitizing cyanine dyes used in the present invention are cyanines (in a narrow sense), mercocyanine dyes, hemicyanine dyesllhe preferred. compounds are repreful because of having excellent solubility and good sensititizing action.

The following examples are provided to illustrate the invention but are not intended to limit the same.

Example 1 This example illustrates that the dissolution method of the present invention is excellent.

One part by weight of Dye (I) was dissolved in 4,000 parts by weight of a 1% aqueous solution of sodium dodecylsulfate, 4,000 parts by weight of a 1% aqueous solution of oleyl-N-methyl sodium tauride, 4,000 parts by weight of a 1% aqueous solution of p-nonylphenoxyethoxy-ethoxyethylsulfonic acid or 4,000 parts by weight of a 2% aqueous solution of saponin. In this method, the dye easily dissolved, and precipitation of crystals was not observed even upon standing for two weeks at room temperature. However, when 1 part by weight of the same dye was added to 4,000 parts by weight of methanol, the dye was poorly soluble and crystals precipitated after standing for 3 days at room temperature. This dye was substantially insoluble in distilled water.

Example 2 Dye (II) One part by weight of Dye (III) was dissolved in 4,000 parts by weight of a 1% aqueous solution of sodium dodecylsulfate, 4,000 parts by weight of a 1% aqueous solution of sodium dodecylbenzenesulfonate, 4,000 parts by weight of a 1% aqueous solution of sodium oleate or 4,000 parts by weight of a 2% aqueous solution of saponin. The dye dissolved very easily and precipitation of crystals was not observed even upon standing for 2 weeks at room temperature. This dye was substantially insoluble in distilled water.

Dye (III) CzHs dHmsmHNQ The above examples illustrate the excellence and eas of practice using the present invention.

8 Example 4 This example illustrates that aqueous dye solutions prepared by the dye dissolution method of the present invention have excellent stability.

Dyes II (Example 2), III (Example 3) and IV (Example 4) were dissolved, respectively, in 1% aqueous solutions of the above described surface active agents 5, 7, 10, 11, 12, 16,21, 22, 28 and 30. After standing for 14 days at room temperature, the spectral density of the solutions was determined by diluting with an aqueous solution of the same surface active agent. The ratio of the dye remaining in the solution was determined from the density values of the absorption maximum before and after standing. The results are shown in Table 1.

Dye (IV) Surface active agents:

SOzNB CrzHzs- TABLE 1.STABILITY OF AQUEOUS SURFACE ACTIVE AGENT SOLUTIONS OF DYES III Dye

Suriiwe active agent:

wherein:

Dye remaining (ratio) Example 5 This example illustrates dye solutions prepared according to the dye dissolution method of the present invention exhibits an excellent sensitizing action.

A dye solution was prepared by dissolving 1 part by weight of Dye (II) in 4,000 parts by weight of methanol (control). A further dye solution was prepared by dissolving 1 part by weight of Dye (II) in 2,000 parts by weight of a. 1% aqueous solution of sodium dodecylsulfate. These dye solutions were added to a silver chloride bromide (Br: 60% mol, Cl: 40% mol) emulsion containing a sulfur sensitizer and a gold salt sensitizer, prepared by known methods to provide 0.045 g. of the dye per mol of silver halide. After standing for 10 minutes at 40 C., stabilizers and a hardening agent were added to the emulsions. The resulting emulsions were then applied to a cellulose triacetate film support. The samples were subjected to sensitometric exposure through a green filter through which rays having a wavelength range of 500 mp.- 600 mu passed, and then developed using a known black the developing agents.

In Table 2, the green-exposure relative speed, gamma and fog of the resulting emulsions are shovvn.

TABLE '2 Sample (d ssolved in Control aqueous surface (dissolved in active agent Sensitive material methanol) solutions) Photographic property: I

Relative speed 100 105 Gamma 3; 10V 3. Fog 0. 10 0. 10

Example 6 This example also illustrates dye solutions prepared according to the dye dissolution method of the present invention exhibits an excellent sensitizing action.

A dye solution was prepared by dissolving 1 part by weight of Dye (I) in 4,000 parts by weight of. methanol (control). A further dye solution was prepared by dissolving 1 part by weight of Dye (I) in 4,000 parts by weight of a 1% aqueous solution of oleyl-N-methyl sodium tauride. These dye solutions were added to a silver chloride bromide (Br: 30% mol,,Cl: 70% mol) emulsion to provide 0.065 g. of the dye per mol of silver halide. After adding stabilizers and hardening agents, 150 g. of N-n-dodecyl-1-hydroxy-4-chloro-Z-naphthamide per 1 mol of silver halide as the color former (emulsified in dibutylphthalate) was added to the emulsions. The emulsions were coated onto a cellulose triacetate film support. After drying, the resulting samples were subjected to sensitometric exposure through a red filter through which rays having a wavelength range of 600 mu700 m passed, and then developed with using a known developer comprising 4-N-N-diethylam' 7 2f methyla' nilinef'hydrbchloride, as the' color develo rigagent- Af r staiidardfbleaehingarid fixing treatments, a cyan color image jwas fornied. In Table 3, [he red-exposure relative speejd, gammaa'h of the resulting emulsiqn'sare showriL .m TABIJEB 'samp1e t. a! l g ?(d1ssolved.=in I I Control .q uem surtaqe "(dissolved in active a ent Sensitive material .methanol) solutions) Photographic pi 'bp Relative speed I, Gamma. 2.85 Fog 0.0a EXAMPLE 7' v. vThis example further illustrates d ye solutions prepared according. to the dye-dissolution method of the. present invention. exhibits .an excellent sensitizingaction.

-A dye solution was prepared by dissolving 1 part, by weight of- Dye (II in 4,00( .parts by weight of methanol t ol)- dye Q Z fl$ ;a S.P3 1239 y d ssolvin 1 part-by weight of. Dye -(III)'in 4,000 parts by weight of a 21% aqueous saponin solution. These, dyes solutions were added to a silver iodobromide (I: 6%mol, Br: 94% mol) emulsion containing a sulfur sensitizer and a gold salt sensitizer, prepared by known methods to provide 0.050 g. of th e dyeper mol of silver halide. After adding astabilizer and a hardening agent, 180 g. of 2-(2,4 -di(t)-amy1- phenoxy-acetamide)-4,6-dichloro-5-methyl phenohper 1 mol of silver halide (emulsified in dibutylphthalate) was added to the emulsions. The emulsions were then coated onto a cellulose triacetate film support. After drying, the samples wer esubjected to ,sensitometric exposure by the same procedure as in Example GL-The, sample vve re developedhwith a. developer comprising l amf I Ii -ethyl- N- (methylsulfo-amido-ethyl).r,1n,- toluidi ne ses'quisulf ate monohydrate as the color developing agen After standarib aeh' d fix a eatmsme a are q rtimae n Table 4,.red exposure ,relative sensiti ty',,

.tqao efgesultin .mulsipas are al-12 What is claimed is:

1. In a process for producing silver halide photographic emulsions containing a photographic sensitizing dye or densensitizing dye, the improvement which comprises directly dissolving said photographic dye in a system consisting essentially of water and a surface active material having a hydrophilic group selected from the group consisting of SO OSO or COO- and adding the resulting solution to the silver halide photographic emulsion.

2. A process as claimed in Claim 1 wherein a hydrophobic group of the surface active agent is selected from aromatic groups substituted by saturated or unsaturated hydrocarbon groups having up to 18 carbon atoms and aliphatic hydrocarbon groups having up to 20 carbon atoms.

3. A process as claimed in Claim 1 wherein the photographic dye is selected from those represented by the general formulae (I), (II), (III), (IV) and (V):

m represents 1, 2 or 3; H

d represents 1, 2 or 3;

X- represents an acid group;

Z and Z each represent the group of atoms necessary to complete a or 6-membered heterocyclic ring customarily employed as the cyanine nucleus;

P and Q each represent CN and COOR (R represents an alkyl group) or P and Q may form a heterocyclic ring by ring closure;

Y and Y each represent an atom or group of atoms necessary to complete a S-membered heterocyclic ring customarily employed as the merocyanine nucleus.

4. A process as claimed in Claim 3 which in the photographic dyes are those having a SO; or COO- group.

5. A process for producing a photographic light-sensitive material which comprises applying the silver halide photographic emulsion as claimed in Claim 1 to a support at a rate of 30 m./minute-160 m./minute.

6. A process as claimed in Claim 3 wherein the substituted alkyl group for R and R is selected from the group consisting of a hydroxy-alkyl group, an acetoxyalkyl group, an alkyl group containing a sulfo group, an alkyl group containing a carboxy group, an allyl group and an alkyl sulfate group; wherein the methine group is selected from the group consisting of =CH,

and =O(aryl)-; wherein the 5- or 6-membered heterocyclic ring completed by Z is selected from the group consisting of thiazoles, benzothiazoles, naphthothiazoles, oxazoles, benzoxazoles, selenazoles, benzoselenazoles, naphthoselen'azoles, nap'thoxazoles, thiazolines, oxazolines, selenazolines, 2-qu'inolines, 4 quinolines, 3,3 dialkylindolenines and benzimidazoles; wherein the 5- or 6-membered heterocyclic ring completed by Z is selected from the group consisting of thiazoles, benzothiazoles, naphthothiazoles, oxazoles, benzoxazoles, selenazoles, napthoxazoles, thiazolines, 2-quinolines and benzimidazoles, wherein the heterocyclic ring formed by P and Q is selected from the group consisting of pyrazolones, isoxazolones, oxindole, 2,4,6-triketohexahydropyrimidines, 2- thio-2,4-thiazolidine-diones, 2-thio-2,4 oxazolidinediones, 2-thio-2,'5-thiazolidine-diones, 2,4-thiazolidione-diones, 4- thiazolidinones, 4-thiazolinones, 2-imino-2,4-oxazolidinediones, 2,4imidazolidinediones, 2-thio- 2,4-imidazolidinedones and S-imidazolinones; wherein the S-membered heterocyclic ring completed by Y and Y is selected by the group consisting of 4-oxazolidinone, 5-oxazolidinone, 4-thiazolidinone, S-thiazolidinone and 4-imidazolidinone.

7. A process as claimed in Claim 6 wherein the alkyl group containing a sulfo group or a carboxy group is selected from the group consisting of a fl-sulfoethyl group, a 'y-sulfopropyl group, a a-sulfobutyl group, a p-sulfoethoxyethyl group and a carboxyethyl group.

8. A process as claimed in Claim 1, wherein the surface active material is selected from the group consisting of sodium dodecylsulfate, oleyl-N-methyl sodium tauride, p-nonylphenoxy-e'thoxyethoxyethylsulfonic acid, saponin, sodium dodecylbenzenesulfonate, sodium oleate,

uHaa-C O-ITT-CHzCHzS OaNa S OaNa CH3 CnHzH I-omo 0 0 CnHza-C O ONa nHaa-C 0 ONa and (CHzCH20)nH 14 2n-N(CHzCHzO) H p and q each represent a positive integer where p+q=5.

9. A process as claimed in Claim 1 wherein said dye is water insoluble.

10. A process as claimed in Claim 1 in which the photographic dyes are those having a SO group.

11. A process as claimed in Claim 1 in which the photographic dyes are those having a OSO; group.

12. A process as claimed in Claim 1 in which the photogrophic dyes are those having a COO group.

13. A process as claimed in Claim 1 wherein water is the sole solvent.

14. LA. process as claimed in Claim 1 wherein the amount of the surface active agent present is greater than the critical concentration for the formation of micelles of the surface active agent.

15. A process as claimed in Claim 1 wherein the dye is poorly soluble in organic solvents.

16. A process as claimed in Claim 1 wherein the dye in nondissolved form is added to an aqueous solution of the surface active agent and water as the sole solvent, whereby the photographic emulsion formed illustrates excellent photographic speed.

References Cited UNITED STATES PATENTS 2,275,727 3/1942 Carroll et a1 96126 3,457,078 7/1969 lRiester 96-126 3,481,742 12/ 1969 Terashima et a1 96126 3,658,546 4/ 1972 Van Doorselaer et a1. 96'1Q0 3,660,101 5/1972 Owens et al. 96120 FOREIGN PATENTS =1,154,7-81 6/'1969 Great Britain 96114.5

J. TRAVIS BROWN, Primary Examiner US. Cl. XIR. 

